I. Field
The invention relates to communication systems and, more particularly, to synchronization between access routers in wireless communication systems.
II. Background
Communication systems frequently include a number of network nodes through which end nodes (e.g., mobile devices) communicate. End nodes communicate with network nodes directly through connections that have been established with the network nodes. Such systems usually rely on the existence of a bidirectional communications link between an end node and an access node to support two-way communications. In such systems, the end node may not know the network layer address of a target destination network node but may be aware of information that it can receive over broadcast channels.
In some systems, end nodes are capable of maintaining multiple bidirectional communications links with different network nodes at substantially the same time. However, such systems typically require the end nodes to send messages intended for a specific network node, with which the end node has a connection, over the link that is directly connected to that specific network node. This approach might not be efficient in some situations especially for wireless link that can fluctuate in terms of quality (e.g., delay and loss characteristics). As a result, the link to the target destination network node may not be the best link available to the end node at the time a message is to be sent to the network node. Typically, this limitation is overcome by resorting to network layer communications that can be routed through multiple hops due to the user of network layer addresses (e.g., IP addresses). This approach of using network layer address may not be efficient especially when the messaging relates to link layer specific functions because network layer messages can be much larger than link layer messages in some systems. In addition, inefficient signaling is not suitable for communications over resource restricted air links.
Network nodes that are serving neighboring geographical cells are typically known to each other through a manual configuration. During such configuration, various parameters are configured in a network node corresponding to several of its neighbors. Such configuration is typically labor intensive and error prone due to human error and the fact that the network layout of a wireless networks often changed relevant to a gradual phased deployment of a wireless communications system.
In addition, the network nodes might not be aware of which of the other network nodes are serving the same end node. Thus, if there is a change in the state of the end node, it is unknown which, if any, of the other network nodes should have the state change information. This information regarding the state of the end node is important to maintain a consistent and reliable user experience.
Therefore, to overcome the aforementioned as well as other deficiencies, there is a need to communicate the state change information efficiently to maintain synchronization between network nodes.